You can get 1.122 GH/s at 422W. That's 2.66 MH/W.Roadhog2k5 can get 1.65 GH/s at 624W. That's 2.64 MH/W.

2.72 > 2.66.2.72 > 2.64.

And don't forget that your 5970s aren't even undervolted either. The 7970s have to be undervolted to even get close to a 5970, and once they do so, they're down close to 200 MH/s compared to a 5970. I wonder what kind of power a 5970 would use if you undervolt it and crank it down to 550 MH/s. Hmm!

I'm a little fuzzy why people are comparing a dual chip card to a single chip card. The apples to apples comparison comes when the 7990 is released. Even then comparing a brand new card at full price vs cards bought well after their EOL ie they are cheaper than launch price has to be factored in.

I'm a little fuzzy why people are comparing a dual chip card to a single chip card. The apples to apples comparison comes when the 7990 is released. Even then comparing a brand new card at full price vs cards bought well after their EOL ie they are cheaper than launch price has to be factored in.

Because we are comparing the newest card to the current best card to see if it is worth buying!

^This. If we're going to compare, let's compare "apples to apples". Comparing to 5970's in general isn't realistic or accurate. This is why I compared to 5870s. When the 7990 comes out in March, THEN we can compare against 5970's with accuracy.

You can get 1.122 GH/s at 422W. That's 2.66 MH/W.Roadhog2k5 can get 1.65 GH/s at 624W. That's 2.64 MH/W.

2.72 > 2.66.2.72 > 2.64.

And don't forget that your 5970s aren't even undervolted either. The 7970s have to be undervolted to even get close to a 5970, and once they do so, they're down close to 200 MH/s compared to a 5970. I wonder what kind of power a 5970 would use if you undervolt it and crank it down to 550 MH/s. Hmm!

I'm a little fuzzy why people are comparing a dual chip card to a single chip card. The apples to apples comparison comes when the 7990 is released. Even then comparing a brand new card at full price vs cards bought well after their EOL ie they are cheaper than launch price has to be factored in.

Even then comparing a brand new card at full price vs cards bought well after their EOL...

The new cards are using a new process. We were expecting that the drop in process size would increase hashing efficiency significantly. It's very disappointing seeing the new cards barely hold their own against a 2 year old card when comparing performance per watt.

I'm a little fuzzy why people are comparing a dual chip card to a single chip card. The apples to apples comparison comes when the 7990 is released. Even then comparing a brand new card at full price vs cards bought well after their EOL ie they are cheaper than launch price has to be factored in.

Because it is the reality of the situation on the ground right now.

If you have $3K to build some GPU based rigs you essentially got 4 choices.

Who cares what the apples to apples comparison will be in 2-3 months. In 2-3 months people will evaluate what is available at that time.

The reality is which capital investment gives me the best return. Period.

The fact that it is a dual gpu or single gpu is irrelivent. The FPGA boards have both dual and single chip designs. It would make no sense to say board X is the BEST (except if you look at dual chip boards) or vice versa.

Even then comparing a brand new card at full price vs cards bought well after their EOL...

The new cards are using a new process. We were expecting that the drop in process size would increase hashing efficiency significantly. It's very disappointing seeing the new cards barely hold their own against a 2 year old card when comparing performance per watt.

OP's system uses lots of power but performance per watt for cards only is higher than for any other gpu. ~3.9MH/s/W vs. ~2.3MH/s/W 5970

Even then comparing a brand new card at full price vs cards bought well after their EOL...

The new cards are using a new process. We were expecting that the drop in process size would increase hashing efficiency significantly. It's very disappointing seeing the new cards barely hold their own against a 2 year old card when comparing performance per watt.

3200 stream processors vs 2048. That's what matters the most no? Dual chip cards are a little more efficient than two separate cards. You gain by getting rid of duplication.

OP's system uses lots of power but performance per watt for cards only is higher than for any other gpu. ~3.9MH/s/W vs. ~2.3MH/s/W 5970

A card without a system performs at 0 MH/s/W. The only valid comparison is a complete system.

how do you choose a card then?

imho to compare cards it is essential to benchmark them as separate from the system as possible. of course in the end it comes down to the whole rig. but it is irrelevant for the efficiency of the cards if I e.g. connect a heater to my powersupply.

All of my dedicated miners are usually using a headless Ubuntu install on a flash drive, but since there probably aren't any programs for Linux that will allow me to change the clocks/voltage on these cards yet (besides what's allowed in aticonfig), I'm using Windows to test this.

If you still think these cards aren't efficient, you're drunk. If they were still using VLIW, they'd be insane at hashing. All GPUs show 99 percent utilization. If small improvements can be made to the miner kernels, efficiency will be further improved.

I've got a small external fan blowing on the rig (as with all of my mining rigs). The temps on these cards while mining at 2060 Mhash/sec are 63/64/65/61C. The fan speeds on auto are adjusting to 30/30/30/27% respectively.

All wattages were read with a Kill-a-watt (which makes the measurements on the AC side, of course).

^This. Also, I have no idea what power supply the OP is using. If is PSU is heavily loaded, efficiency will drop. I was using a Seasonic X-1250 which is built incredibly well. It's rated for 104A on the 12V rail alone. Me only loading it 50-60 percent makes things that much better. ...not to mention that the PSU is just efficient in the first place.

^This. Also, I have no idea what power supply the OP is using. If is PSU is heavily loaded, efficiency will drop. I was using a Seasonic X-1250 which is built incredibly well. It's rated for 104A on the 12V rail alone. Me only loading it 50-60 percent makes things that much better. ...not to mention that the PSU is just efficient in the first place.

I have a corsair AX1200. Has about 90-92% efficiency through its range.